Nested for loops froze the browser - javascript

I am trying to calculate Moore neighborhood.
If I set the loop to execute 10 times each (10x10 dimension), it works but when I change them to 20 times each (20x20 dimension), it froze the browser.
Why did it freeze?
var c_canvas = document.getElementById("c");
var context = c_canvas.getContext("2d");
var step = 20;
var n = 20,
m = 20;
var population = [];
var MIN_X = 0;
var MIN_Y = 0;
var MAX_X = 19;
var MAX_Y = 19;
for (var i = 0; i < m; i++) {
population[i] = [];
for (var j = 0; j < n; j++) {
population[i][j] = 0;
}
}
for (var x = 0; x < step; x++) {
context.beginPath();
context.moveTo(x * step, 0);
context.lineTo(x * step, step * step);
context.closePath();
}
for (var y = 0; y < step; y++) {
context.beginPath();
context.moveTo(0, y * step);
context.lineTo(step * step, y * step);
context.closePath();
}
function redrawGrid() {
for (var r = 0; r < step; r++) {
for (var z = 0; z < step; z++) {
var temp = population[r][z]
if (temp == 0) {
context.beginPath();
context.rect(r * step, z * step, step, step);
context.fillStyle = 'white';
context.fill();
context.closePath();
};
if (temp == 1) {
context.beginPath();
context.rect(r * step, z * step, step, step);
context.fillStyle = 'red';
context.fill();
context.closePath();
};
if (temp == 2) {
context.beginPath();
context.rect(r * step, z * step, step, step);
context.fillStyle = 'black';
context.fill();
context.closePath();
};
}
}
}
for (var r = 0; r < step; r++) {
for (var z = 0; z < step; z++) {
var temp = randomIntFromInterval(0, 2);
population[r][z] = temp;
if (temp == 0) {
context.beginPath();
context.rect(r * step, z * step, step, step);
context.fillStyle = 'white';
context.fill();
context.closePath();
};
if (temp == 1) {
context.beginPath();
context.rect(r * step, z * step, step, step);
context.fillStyle = 'red';
context.fill();
context.closePath();
};
if (temp == 2) {
context.beginPath();
context.rect(r * step, z * step, step, step);
context.fillStyle = 'black';
context.fill();
context.closePath();
};
}
}
var startPosX;
var startPosY;
var endPosX;
var endPosY;
var ownColor;
var otherColor;
function moor(i, j) {
ownColor = 0;
otherColor = 0;
startPosX = (i - 1 < MIN_X) ? i : i - 1;
startPosY = (j - 1 < MIN_Y) ? j : j - 1;
endPosX = (i + 1 > MAX_X) ? i : i + 1;
endPosY = (j + 1 > MAX_Y) ? j : j + 1;
for (var rowNum = startPosX; rowNum <= endPosX; rowNum++) {
for (var colNum = startPosY; colNum <= endPosY; colNum++) {
if (rowNum == i && colNum == j) {} else {
if (population[rowNum][colNum] == 1)
ownColor++;
if (population[rowNum][colNum] == 2)
otherColor++;
}
}
}
if (ownColor == 0) {
return 0;
} else
return otherColor / ownColor;
}
function randomIntFromInterval(min, max) {
return Math.floor(Math.random() * (max - min + 1) + min);
}
context.strokeStyle = "#ddd";
context.stroke();
//population[0][0] = 0;
//setTimeout("redrawGrid()", 500);
var rand1;
var rand2;
var temp;
var i;
var j;
for (i = 0; i < 10; i++) {
for (j = 0; j < 10; j++) {
if (moor(i, j) > moor(i + 1, j)) {
temp = population[i][j];
rand1 = randomIntFromInterval(0, 19);
rand2 = randomIntFromInterval(0, 19);
population[i][j] = population[rand1, rand2];
population[rand1][rand2] = temp;
}
}
}
<canvas id="c"></canvas>

Related

Is it possible to run a function updating a grid using a Web Worker?

I have a block of code that i want to try and run on a Web worker but i can't get it to work because "document." is not defined in a worker. So i was wondering if it is even possible to run code like this on a worker. Can it get click events and so on.
The code creates a grid on a canvas and sets a clearRect where you click.
//Declare varibles
const canvas = document.getElementById('canvas');
const ctx = canvas.getContext('2d');
var cellSize = 12;
var gridColor = "#1f1f1f";
var largeGridColor = "#2e2e2e";
//set canvas resolution to screen resolution
ctx.canvas.width = 1920;
ctx.canvas.height = 932;
var cellsInRow = parseInt(ctx.canvas.height/cellSize);
var cellsInCollum = parseInt(ctx.canvas.width/cellSize);
//create array
let arry = [];
for(var i = 0; i < cellsInRow; i++){
arry[i] = [];
for(var j = 0; j < cellsInCollum; j++){
arry[i][j] = 0;
}
}
let arryOld = arry.map(row => [...row]);
//draw on canvas
setInterval(drawCells, 1);
canvasBackground();
canvasGrid();
randomStartPattern()
function getCursorPointer(canvas, event){
const rect = canvas.getBoundingClientRect();
let scaleX = canvas.width / rect.width;
let scaleY = canvas.height / rect.height;
const x = (event.clientX - rect.left)*scaleX;
const y = (event.clientY - rect.top)*scaleY;
console.log("x: " + x + " y: " + y);
let xP = (x);
let yP = (y);
setCell(xP, yP);
}
canvas.addEventListener('mousedown', function(e){
getCursorPointer(canvas, e);
});
function setCell(x, y){
for(var i = 0; i < cellsInRow; i++){
for(var j = 0; j < cellsInCollum; j++){
if((y >= (i*cellSize) && y <= ((i*cellSize)+cellSize-1)) &&(x >= (j*cellSize) && x <= ((j*cellSize)+cellSize-1))){
if(arry[i][j] == 0){
arry[i][j] = 1;
}else{
arry[i][j] = 0;
}
}
}
}
}
function drawCells(){
for(var i = 0; i < cellsInRow; i++){
for(var j = 0; j < cellsInCollum; j++){
if(arry[i][j] == 1){
ctx.clearRect(j * cellSize+1, i * cellSize+1, cellSize-2, cellSize-2);
}else{
ctx.fillStyle ="black";
ctx.fillRect(j * cellSize+1, i * cellSize+1, cellSize-2, cellSize-2);
}
}
}
}
function canvasBackground(){
ctx.fillStyle = 'black';
ctx.fillRect(0, 0, canvas.width, canvas.height);
}
function canvasGrid(){
for(var i = 0; i < cellsInRow; i++){
if(i%10 == 0){
ctx.strokeStyle = largeGridColor;
}else{
ctx.strokeStyle = gridColor;
}
ctx.beginPath();
ctx.moveTo(0, i*cellSize);
ctx.lineTo(canvas.width, i*cellSize);
ctx.lineWidth = 1;
ctx.stroke();
for(var j = 0; j < cellsInCollum; j++){
if(j%10 == 0){
ctx.strokeStyle = largeGridColor;
}else{
ctx.strokeStyle = gridColor;
}
ctx.beginPath();
ctx.moveTo(j*cellSize, 0);
ctx.lineTo(j*cellSize, canvas.height);
ctx.lineWidth = 1;
ctx.stroke();
}
}
}
function randomStartPattern(){
for(var i = 0; i < cellsInRow; i++){
for(var j = 0; j < cellsInCollum; j++){
let rand = Math.random();
if(rand < 0.5){
arry[i][j] = 1;
}else{
arry[i][j] = 0;
}
}
}
}
It should works smth like this:
/// ================= MAIN SCRIPT ====================
const worker = new Worker('./your_worker.js');
function getCursorPointer(canvas, event){
const rect = canvas.getBoundingClientRect();
let scaleX = canvas.width / rect.width;
let scaleY = canvas.height / rect.height;
const x = (event.clientX - rect.left)*scaleX;
const y = (event.clientY - rect.top)*scaleY;
console.log("x: " + x + " y: " + y);
worker.postMessage({x, y});
}
canvas.addEventListener('mousedown', function(e){
getCursorPointer(canvas, e);
});
const offscreen = canvas.transferControlToOffscreen();
worker.postMessage({offscreen}, [offscreen]);
Here you works with DOM, and pass events to worker using postMessage
// ==================== WORKER CODE ===========================
let ctx;
const arry = [];
onmessage = function({data}) {
if(data.offscreen) {
ctx = data.offscreen.getContext("2d");
canvasBackground();
canvasGrid();
randomStartPattern()
setInterval(drawCells, 1);
} else {
setCell(data.x, data.y);
}
});
function drawCells(){
for(var i = 0; i < cellsInRow; i++){
for(var j = 0; j < cellsInCollum; j++){
if(arry[i][j] == 1){
ctx.clearRect(j * cellSize+1, i * cellSize+1, cellSize-2, cellSize-2);
}else{
ctx.fillStyle ="black";
ctx.fillRect(j * cellSize+1, i * cellSize+1, cellSize-2, cellSize-2);
}
}
}
}
function randomStartPattern(){
for(var i = 0; i < cellsInRow; i++){
for(var j = 0; j < cellsInCollum; j++){
let rand = Math.random();
if(rand < 0.5){
arry[i][j] = 1;
}else{
arry[i][j] = 0;
}
}
}
}
function setCell(x, y){
for(var i = 0; i < cellsInRow; i++){
for(var j = 0; j < cellsInCollum; j++){
if((y >= (i*cellSize) && y <= ((i*cellSize)+cellSize-1)) &&(x >= (j*cellSize) && x <= ((j*cellSize)+cellSize-1))){
if(arry[i][j] == 0){
arry[i][j] = 1;
}else{
arry[i][j] = 0;
}
}
}
}
}
function canvasBackground(){
ctx.fillStyle = 'black';
ctx.fillRect(0, 0, canvas.width, canvas.height);
}
function canvasGrid(){
for(var i = 0; i < cellsInRow; i++){
if(i%10 == 0){
ctx.strokeStyle = largeGridColor;
}else{
ctx.strokeStyle = gridColor;
}
ctx.beginPath();
ctx.moveTo(0, i*cellSize);
ctx.lineTo(canvas.width, i*cellSize);
ctx.lineWidth = 1;
ctx.stroke();
for(var j = 0; j < cellsInCollum; j++){
if(j%10 == 0){
ctx.strokeStyle = largeGridColor;
}else{
ctx.strokeStyle = gridColor;
}
ctx.beginPath();
ctx.moveTo(j*cellSize, 0);
ctx.lineTo(j*cellSize, canvas.height);
ctx.lineWidth = 1;
ctx.stroke();
}
}
}
Here you works with canvas context, store your arry and catch events from main page by onmessage

An error in the checkers code, how to fix it?

Made a small game, the main goal is to remove all the pieces by jumping over the checkers. The first time it is possible to remove the checker, the second time it gives an error?
Uncaught TypeError: Cannot read property 'theRow' of undefined
On line 180. I looked at the line, here it is.
Code:
Point = function(x, y) {
this.x = x;
this.y = y;
}
window.onload = function() {
var canvas;
var context;
var BB;
var offsetX;
var offsetY;
var dragok = false;
var startX;
var startY;
var oldX, oldY;
var fieldArray = [
[1, 0, 1, 1, 0, 0],
[1, 0, 0, 1, 1, 0],
[0, 0, 0, 0, 0, 0]
];
var shapes = [];
var possibleLandings = [];
var localX, localY;
var pickedMonster;
var sx = 0;
var sy = 0;
var i1 = 0;
function draw() {
context.clearRect(0, 0, canvas.width, canvas.height);
context.save();
for (var i = 0; i < fieldArray.length; i++) {
for (var j = 0; j < fieldArray[i].length; j++) {
context.lineWidth = 1;
context.strokeRect(j * 60, i * 60, 60, 60);
context.fillRect(j * 60, i * 60, 60, 60);
}
}
for (var i = 0; i < shapes.length; i++) {
circle(shapes[i]);
}
context.restore();
if (possibleLandings.length > 0) {
context.save();
context.fillStyle = "#4CFF00";
context.fillRect(oldX, oldY, 20, 20);
context.restore();
} else {
context.save();
context.fillStyle = "#FF0000";
context.fillRect(oldX, oldY, 20, 20);
context.restore();
}
}
function circle(c) {
context.fillStyle = c.fill;
context.beginPath();
context.arc(c.x, c.y, c.r, 0, Math.PI * 2);
context.closePath();
context.fill();
}
function myDown(e) {
e.preventDefault();
e.stopPropagation();
var mx = parseInt(e.clientX - offsetX);
var my = parseInt(e.clientY - offsetY);
dragok = false;
for (var i = 0; i < shapes.length; i++) {
var s = shapes[i];
var dx = s.x - mx;
var dy = s.y - my;
if (dx * dx + dy * dy < s.r * s.r) {
dragok = true;
s.isDragging = true;
pickedMonster = {
x: s.x,
y: s.y,
i: i,
theRow: s.theRow,
theCol: s.theCol
};
oldX = s.x;
oldY = s.y;
localX = mx - s.x + (30 / 2);
localY = my - s.y + (30 / 2);
checkMonster(s);
canvas.onmousemove = moveMonster;
canvas.onmouseup = dropMonster;
}
}
startX = mx;
startY = my;
}
function moveMonster(e) {
if (dragok) {
e.preventDefault();
e.stopPropagation();
var mx = parseInt(e.clientX - offsetX);
var my = parseInt(e.clientY - offsetY);
var dx = mx - startX;
var dy = my - startY;
for (var i = 0; i < shapes.length; i++) {
var s = shapes[i];
if (s.isDragging) {
s.x += dx;
s.y += dy;
pickedMonster.x = e.clientX - localX;
pickedMonster.y = e.clientY - localY;
}
}
draw();
startX = mx;
startY = my;
}
}
function dropMonster(e) {
e.preventDefault();
e.stopPropagation();
var legalMove = false;
var dropX = Math.floor((pickedMonster.x + 30) / 60);
var dropY = Math.floor((pickedMonster.y + 30) / 60);
console.log(dropX);
for (var i = 0; i < possibleLandings.length; i++) {
if (possibleLandings[i].x == dropY && possibleLandings[i].y == dropX) {
legalMove = true;
break;
}
}
if (!legalMove) {
shapes[pickedMonster.i].x = oldX;
shapes[pickedMonster.i].y = oldY;
} else {
var rowOffset = (dropY - pickedMonster.theRow) / 2;
var colOffset = (dropX - pickedMonster.theCol) / 2;
fieldArray[pickedMonster.theRow][pickedMonster.theCol] = 0;
fieldArray[pickedMonster.theRow + rowOffset][pickedMonster.theCol + colOffset] = 0;
fieldArray[pickedMonster.theRow + 2 * rowOffset][pickedMonster.theCol + 2 * colOffset] = 1;
for (i = 0; i < 5; i++) {
var currentMonster = shapes[i];
if (currentMonster.theRow == pickedMonster.theRow + rowOffset &&
currentMonster.theCol == pickedMonster.theCol + colOffset) {
shapes.splice(i, 1);
}
}
}
dragok = false;
for (var i = 0; i < shapes.length; i++) {
shapes[i].isDragging = false;
}
draw();
}
function checkMonster(s) {
for (var i = 0; i < 4; i++) {
var deltaRow = (1 - i) * (i % 2 - 1);
var deltaCol = (2 - i) * (i % 2);
if (checkField(s, deltaRow, deltaCol)) {
possibleLandings.push(new Point(s.theRow + 2 * deltaRow, s.theCol + 2 * deltaCol));
}
}
}
function checkField(s, rowOffset, colOffset) {
if (fieldArray[s.theRow + 2 * rowOffset] != undefined &&
fieldArray[s.theRow + 2 * rowOffset][s.theCol + 2 * colOffset] != undefined) {
if (fieldArray[s.theRow + rowOffset][s.theCol + colOffset] == 1 &&
fieldArray[s.theRow + 2 * rowOffset][s.theCol + 2 * colOffset] == 0) {
return true;
}
}
return false;
}
function main() {
canvas = document.getElementById("drawingCanvas"),
context = canvas.getContext("2d");
canvas.style.background = "#A0A0A0"
BB = canvas.getBoundingClientRect();
context.fillStyle = 'rgb(150,190,255)';
context.globalAlpha = 0.7;
offsetX = BB.left;
offsetY = BB.top;
for (var i = 0; i < fieldArray.length; i++) {
for (var j = 0; j < fieldArray[i].length; j++) {
if (fieldArray[i][j] == 1) {
shapes.push({
x: j * 60 + 30,
y: i * 60 + 30,
r: 30,
theRow: i,
theCol: j,
fill: "#444444",
isDragging: false
});
}
}
}
draw();
canvas.onmousedown = myDown;
}
main();
}
<canvas id="drawingCanvas" width="500" height="500">
How to fix?
At the end of the game shapes is empty but you are getting shapes[i]. That would return undefined. And that's what the error means undefined doesn't have a property theRow.
You should maybe rerun main() or only rerun this:
for (var i = 0; i < fieldArray.length; i++) {
for (var j = 0; j < fieldArray[i].length; j++) {
if (fieldArray[i][j] == 1) {
shapes.push({
x: j * 60 + 30,
y: i * 60 + 30,
r: 30,
theRow: i,
theCol: j,
fill: "#444444",
isDragging: false
});
}
}
}

Removing mouse controls from Javascript code

I have a large piece of code that draws feather-looking designs controlled by the mouse. This is using mouse pressed and mouseX, mouseY.
I would like the code to run and draw the feathers without the mouse being involved (ie. opening the canvas and having feathers automatically draw on the screen).
The full code is below:
var points = [];
var painting = false;
var strokeNumber = 0;
var scl = 6;
var cols, rows;
var inc = 0.1;
var zOff = 0;
var particles = [];
var flowField = [];
var saturation = [];
function setup() {
createCanvas(windowWidth, windowHeight);
// createCanvas(400, 400);
pixelDensity(5);
background(0);
cols = floor(width / scl);
rows = floor(height / scl);
flowField = Array(cols * rows);
saturation = Array(width * height).fill(0);
greateForceField();
}
function mousePressed() {
painting = true;
strokeNumber++;
}
function mouseReleased() {
painting = false;
}
function updateForceField(){
var v = createVector(mouseX, mouseY);
var vPrev = createVector(pmouseX, pmouseY);
v.sub(vPrev);
v.setMag(1);
var i = floor(mouseX / scl);
var j = floor(mouseY / scl);
var index = i * rows + j;
flowField[index] = v;
}
function showForceField(){
for(var i = 0; i < cols; i++){
for(var j = 0; j < rows; j++){
var index = i * rows + j;
var v = flowField[index];
stroke(0,50);
strokeWeight(1);
push();
translate(i * scl, j * scl);
rotate(v.heading());
line(0,0,scl,0);
pop();
}
}
}
function greateForceField(){
var xOff = 0;
for(var i = 0; i < cols; i++){
var yOff = 0;
for(var j = 0; j < rows; j++){
yOff += inc;
var angle = noise(xOff, yOff, zOff) * TWO_PI;
var v = p5.Vector.fromAngle(angle);
v.setMag(.1);
var index = i * rows + j;
flowField[index] = v;
}
xOff += inc;
}
// zOff += inc * 0.1;
}
function draw() {
// background(255);
// showForceField();
if(painting){
updateForceField();
var idx = mouseY * width + mouseX;
if(saturation[idx] < 10){
var r = 1+sqrt(sq(mouseX-pmouseX)+sq(mouseY-pmouseY));
for(var a = 0; a < 100; a++){
var particle = new Particle(mouseX+random()*r*cos(random(TWO_PI)), mouseY+random()*r*sin(random(TWO_PI)));
particles.push(particle);
}
saturation[idx] ++;
}
}
particles.filter(particle => particle.spread > 0).map(particle => {
particle.update();
particle.show();
// particle.edges();
particle.follow();
})
particles.map((particle, idx) => {
if(particle.spread <= 0){
particles.splice(idx,1);
}
});
}
function Particle(x,y){
this.pos = createVector(x,y);
// this.color = color(245, 225, 50);
// this.color = color(145, 225, 192);
this.color = color(255);
this.spread = 127;
this.spreadInc = this.spread/100;
this.prevPos = this.pos.copy();
this.vel = p5.Vector.random2D();
this.acc = createVector(0,0);
this.maxSpeed = 2;
this.update = function(){
this.spread -= this.spreadInc;
this.vel.add(this.acc);
this.vel.limit(this.maxSpeed);
this.pos.add(this.vel);
this.acc.mult(0);
}
this.applyForce = function(force){
this.acc.add(force);
}
this.follow = function(){
var i = floor(this.pos.x / scl);
var j = floor(this.pos.y / scl);
var index = i * rows + j;
var force = flowField[index];
this.applyForce(force);
}
this.show = function(){
stroke(red(this.color),green(this.color),blue(this.color),this.spread);
strokeWeight(.3*this.spread/127);
// point(this.pos.x, this.pos.y);
line(this.pos.x, this.pos.y, this.prevPos.x, this.prevPos.y);
this.updatePrev();
}
this.updatePrev = function(){
this.prevPos = this.pos.copy();
}
this.edges = function(){
if(this.pos.x > width) {
this.pos.x = 0;
this.updatePrev();
}
if(this.pos.x < 0){
this.pos.x = width;
this.updatePrev();
}
if(this.pos.y > height){
this.pos.y = 0;
this.updatePrev();
}
if(this.pos.y < 0) {
this.pos.y = height;
this.updatePrev();
}
}
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/p5.js/0.9.0/p5.js"></script>
Use 4 variables current_x, current_y, prev_x and prev_y instead of mosueX, mouseY, pmouseX and pmouseY.
var current_x=0, current_y=0, prev_x=0, prev_y=0;
function updateForceField(){
var v = createVector(current_x, current_y);
var vPrev = createVector(prev_x, prev_y);
v.sub(vPrev);
v.setMag(1);
var i = floor(current_x / scl);
var j = floor(current_y / scl);
var index = i * rows + j;
flowField[index] = v;
}
Instead of the state painting use a time interval. The time between 2 frames can be get from the built-in variable deltaTime (in milliseconds). Set the x and y positions by random values. e.g.:
var interval = 200; // 200 milliseconds
var sum_time = 0;
function draw() {
sum_time += deltaTime;
if(sum_time > interval){
sum_time = 0;
current_x = Math.floor(random(width));
current_y = Math.floor(random(height));
updateForceField();
prev_x = current_x;
prev_y = current_y;
var idx = current_y * width + current_x;
if(saturation[idx] < 10){
var r = 1+sqrt(sq(current_x-prev_x)+sq(current_y-prev_y));
for(var a = 0; a < 100; a++){
var particle = new Particle(current_x+random()*r*cos(random(TWO_PI)), current_y+random()*r*sin(random(TWO_PI)));
particles.push(particle);
}
saturation[idx] ++;
}
}
// [...]
}
See the example:
var points = [];
var painting = false;
var strokeNumber = 0;
var scl = 6;
var cols, rows;
var inc = 0.1;
var zOff = 0;
var particles = [];
var flowField = [];
var saturation = [];
function setup() {
//createCanvas(windowWidth, windowHeight);
createCanvas(500, 200);
pixelDensity(5);
background(0);
cols = floor(width / scl);
rows = floor(height / scl);
flowField = Array(cols * rows);
saturation = Array(width * height).fill(0);
greateForceField();
}
function mousePressed() {
painting = true;
strokeNumber++;
}
function mouseReleased() {
painting = false;
}
var current_x=0, current_y=0, prev_x=0, prev_y=0;
function updateForceField(){
var v = createVector(current_x, current_y);
var vPrev = createVector(prev_x, prev_y);
v.sub(vPrev);
v.setMag(1);
var i = floor(current_x / scl);
var j = floor(current_y / scl);
var index = i * rows + j;
flowField[index] = v;
}
function showForceField(){
for(var i = 0; i < cols; i++){
for(var j = 0; j < rows; j++){
var index = i * rows + j;
var v = flowField[index];
stroke(0,50);
strokeWeight(1);
push();
translate(i * scl, j * scl);
rotate(v.heading());
line(0,0,scl,0);
pop();
}
}
}
function greateForceField(){
var xOff = 0;
for(var i = 0; i < cols; i++){
var yOff = 0;
for(var j = 0; j < rows; j++){
yOff += inc;
var angle = noise(xOff, yOff, zOff) * TWO_PI;
var v = p5.Vector.fromAngle(angle);
v.setMag(.1);
var index = i * rows + j;
flowField[index] = v;
}
xOff += inc;
}
// zOff += inc * 0.1;
}
var interval = 200; // 200 milliseconds
var sum_time = 0;
function draw() {
// background(255);
// showForceField();
sum_time += deltaTime;
if(sum_time > interval){
sum_time = 0;
current_x = Math.floor(random(width));
current_y = Math.floor(random(height));
updateForceField();
prev_x = current_x;
prev_y = current_y;
var idx = current_y * width + current_x;
if(saturation[idx] < 10){
var r = 1+sqrt(sq(current_x-prev_x)+sq(current_y-prev_y));
for(var a = 0; a < 100; a++){
var particle = new Particle(current_x+random()*r*cos(random(TWO_PI)), current_y+random()*r*sin(random(TWO_PI)));
particles.push(particle);
}
saturation[idx] ++;
}
}
particles.filter(particle => particle.spread > 0).map(particle => {
particle.update();
particle.show();
// particle.edges();
particle.follow();
})
particles.map((particle, idx) => {
if(particle.spread <= 0){
particles.splice(idx,1);
}
});
}
function Particle(x,y){
this.pos = createVector(x,y);
// this.color = color(245, 225, 50);
// this.color = color(145, 225, 192);
this.color = color(255);
this.spread = 127;
this.spreadInc = this.spread/100;
this.prevPos = this.pos.copy();
this.vel = p5.Vector.random2D();
this.acc = createVector(0,0);
this.maxSpeed = 2;
this.update = function(){
this.spread -= this.spreadInc;
this.vel.add(this.acc);
this.vel.limit(this.maxSpeed);
this.pos.add(this.vel);
this.acc.mult(0);
}
this.applyForce = function(force){
this.acc.add(force);
}
this.follow = function(){
var i = floor(this.pos.x / scl);
var j = floor(this.pos.y / scl);
var index = i * rows + j;
var force = flowField[index];
this.applyForce(force);
}
this.show = function(){
stroke(red(this.color),green(this.color),blue(this.color),this.spread);
strokeWeight(.3*this.spread/127);
// point(this.pos.x, this.pos.y);
line(this.pos.x, this.pos.y, this.prevPos.x, this.prevPos.y);
this.updatePrev();
}
this.updatePrev = function(){
this.prevPos = this.pos.copy();
}
this.edges = function(){
if(this.pos.x > width) {
this.pos.x = 0;
this.updatePrev();
}
if(this.pos.x < 0){
this.pos.x = width;
this.updatePrev();
}
if(this.pos.y > height){
this.pos.y = 0;
this.updatePrev();
}
if(this.pos.y < 0) {
this.pos.y = height;
this.updatePrev();
}
}
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/p5.js/0.9.0/p5.js"></script>

Cannot set property "color" of undefined

I'm trying to make a simple candyCrush-like game but I keep getting this error and don't know what to do.
Uncaught TypeError: Cannot set property 'color' of undefined
at testForClick (numbercrunch2.html:50)
at update (numbercrunch2.html:62)
To recreate the error just put some numbers into the text boxes, hit the starting button and click on a random tile.
var c = document.getElementById("canvas");
var ctx = c.getContext("2d");
var tilesX = 0,
tilesY = 0,
tilesWidthX, tilesWidthY, space = 3;
var numb = [];
var mousepos = {
x: 0,
y: 0
},
click = false;
function init(rows, cols) {
tilesWidthX = (canvas.height - rows * 3) / rows;
tilesWidthY = (canvas.height - cols * 3) / cols;
tilesX = rows;
tilesY = cols;
for (var i = 0; i < tilesX; i++) {
numb[i] = [];
for (var j = 0; j < tilesY; j++) {
numb[i][j] = {
val: 1 + Math.round(Math.random() * 6),
color: "grey"
};
ctx.beginPath();
ctx.fillStyle = numb[i][j].color;
ctx.fillRect(space + i * (tilesWidthY + space), space + j * (tilesWidthX + space), tilesWidthY, tilesWidthX);
ctx.closePath();
ctx.beginPath();
ctx.fillStyle = "white";
ctx.font = "20px Arial";
ctx.fillText(numb[i][j].val, 15 + i * (tilesWidthY + space), 30 + j * (tilesWidthY + space), 50);
ctx.closePath();
}
}
}
function testForClick(x, y) {
if (space + x * (tilesWidthX + space) <= mousepos.x && space + y * (tilesWidthY + space) <= mousepos.y && (x + 1) * (tilesWidthX + space) >= mousepos.x && (y + 1) * (tilesWidthY + space) >= mousepos.y) {
numb[x][y].color = "green"; //line 50
}
}
function drawTile(x, y) {
}
function update() {
for (var i = 0; i < 9; i++) {
numb[i] = [];
for (var j = 0; j < 9; j++) {
testForClick(i, j);
drawTile(i, j);
}
}
}
setInterval(update, 300);
function mouseposition(e) {
}
document.getElementById("canvas").addEventListener("click", function(e) {
mousepos.x = e.clientX;
mousepos.y = e.clientY;
}, false);
<canvas id="canvas" height="600" width="600"></canvas>
<form name="formname">
Rows: <input type="text" name="rows"> Columns: <input type="text" name="columns">
<input type="button" value="Start" onClick="init(this.form.rows.value, this.form.columns.value)">
</form>
<div id="t"></div>
Every time you run update() you literally update your numb variable by replacing the previous object for an empty Array object thus when calling testForClick() it has no object in it throwing the error.
function update() {
for (var i = 0;i < 9;i++) {
numb[i] = [];
for ( var j = 0;j < 9;j++) {
testForClick(i,j);
drawTile(i,j);
}
}
} setInterval(update,300);
Should be:
function update()
{
for (var i = 0; i < 9; i++)
{
for (var j = 0; j < 9; j++)
{
testForClick(i, j);
drawTile(i, j);
}
}
};
I created a snippet showing how commenting (or removing) the numb[i] = []; line from update() will make it work.
I updated your script:
// Also, I renamed your 'c' var to 'canvas' because in your init() you are calling it canvas and not 'c'.
var canvas = document.getElementById('canvas');
var ctx = canvas.getContext('2d');
var tilesX = 0, tilesY = 0, tilesWidthX, tilesWidthY, space = 3;
var numb = [];
var mousepos = {x: 0, y: 0}, click = false;
function init(rows, cols)
{
tilesWidthX = (canvas.height - rows * 3) / rows;
tilesWidthY = (canvas.height - cols * 3) / cols;
tilesX = rows;
tilesY = cols;
for (var i = 0; i < tilesX; i++)
{
numb[i] = [];
for (var j = 0; j < tilesY; j++)
{
numb[i][j] = {
val: 1 + Math.round(Math.random() * 6),
color: 'grey'
};
ctx.beginPath();
ctx.fillStyle = numb[i][j].color;
ctx.fillRect(space + i * (tilesWidthY + space), space + j * (tilesWidthX + space), tilesWidthY, tilesWidthX);
ctx.closePath();
ctx.beginPath();
ctx.fillStyle = 'white';
ctx.font = '20px Arial';
ctx.fillText(numb[i][j].val, 15 + i * (tilesWidthY + space), 30 + j * (tilesWidthY + space), 50);
ctx.closePath();
}
}
}
function testForClick(x, y)
{
// Now your 'numb' variable hasn't been changed.
console.log('testForClick', numb);
if (space + x * (tilesWidthX + space) <= mousepos.x && space + y * (tilesWidthY + space) <= mousepos.y && (x+1) * (tilesWidthX + space) >= mousepos.x && (y+1) * (tilesWidthY + space) >= mousepos.y)
{
numb[x][y].color = 'green'; //line 50
}
}
function drawTile(x, y)
{
}
function update()
{
for (var i = 0; i < 9; i++)
{
// Every time you update you replace your object with 'val' and 'color' for an empty array.
// that is the reason why every time you call testForClick you have no object in it.
// Just comment/delete this line so your object never disappears.
// numb[i] = [];
for (var j = 0; j < 9; j++)
{
testForClick(i, j);
drawTile(i, j);
}
}
};
// Changed the interval because I didn't have enough time to enter the rows and columns.
setInterval(update, 5000);
function mouseposition(e)
{
}
document.getElementById('canvas').addEventListener('click', function(e){
mousepos.x = e.clientX;
mousepos.y = e.clientY;
}, false);
SNIPPET:
var canvas = document.getElementById('canvas');
var ctx = canvas.getContext('2d');
var tilesX = 0, tilesY = 0, tilesWidthX, tilesWidthY, space = 3;
var numb = [];
var mousepos = {x: 0, y: 0}, click = false;
function init(rows, cols)
{
tilesWidthX = (canvas.height - rows * 3) / rows;
tilesWidthY = (canvas.height - cols * 3) / cols;
tilesX = rows;
tilesY = cols;
for (var i = 0; i < tilesX; i++)
{
numb[i] = [];
for (var j = 0; j < tilesY; j++)
{
numb[i][j] = {
val: 1 + Math.round(Math.random() * 6),
color: 'grey'
};
ctx.beginPath();
ctx.fillStyle = numb[i][j].color;
ctx.fillRect(space + i * (tilesWidthY + space), space + j * (tilesWidthX + space), tilesWidthY, tilesWidthX);
ctx.closePath();
ctx.beginPath();
ctx.fillStyle = 'white';
ctx.font = '20px Arial';
ctx.fillText(numb[i][j].val, 15 + i * (tilesWidthY + space), 30 + j * (tilesWidthY + space), 50);
ctx.closePath();
}
}
}
function testForClick(x, y)
{
// Now your 'numb' variable hasn't been changed.
console.log('testForClick', numb);
if (space + x * (tilesWidthX + space) <= mousepos.x && space + y * (tilesWidthY + space) <= mousepos.y && (x+1) * (tilesWidthX + space) >= mousepos.x && (y+1) * (tilesWidthY + space) >= mousepos.y)
{
numb[x][y].color = 'green'; //line 50
}
}
function drawTile(x, y)
{
}
function update()
{
for (var i = 0; i < 9; i++)
{
for (var j = 0; j < 9; j++)
{
testForClick(i, j);
drawTile(i, j);
}
}
};
setInterval(update, 5000);
function mouseposition(e)
{
}
document.getElementById('canvas').addEventListener('click', function(e){
mousepos.x = e.clientX;
mousepos.y = e.clientY;
}, false);
<!DOCTYPE html>
<html>
<head>
<title>numbercrunch 2</title>
<meta charset="utf-8">
<style>
canvas {
border: 2px solid black;
}
</style>
</head>
<body>
<canvas id="canvas" height="600" width="600"></canvas>
<form name="formname">
Rows: <input type="text" name="rows">
Columns: <input type="text" name="columns">
<input type="button" value="Start" onClick="init(this.form.rows.value, this.form.columns.value)">
</form>
<div id="t"></div>
</body>
</html>

QR code detection with JavaScript and OpenCV - augmented reality web app

I am working on a augmented reality app for browsers which detects a QR code on a DIN A4 paper and projects an 3D oject in the room.
So far i have a working solution which is working with ARUCO codes, but for my app i need an QR code to project an 3D object in the right perspective. This works also with ARUCO codes, but just on close distance. If the marker is to far away it does not work for me. The solution of this is, to scan a QR code, because the contours can be detected on larger dinstances.
I have a solution which is working with QR codes but the code is wirtten in C++.
I have tried to recode te C++ program to JavaScript.
This is the woking solution which works fine with ARUCO codes in JavaScript:
var JS = http://jeromeetienne.github.io/slides/augmentedrealitywiththreejs/
this is the basic file: https://github.com/jeromeetienne/arplayerforthreejs
This is the code in C++ which is working with QR codes:
var C++ = https://github.com/xingdi-eric-yuan/qr-decoder
So far i have wrote the code from crdecoder.cpp in JavaScript.
Instead of the ARUCO tracking I want wo use the script from qrdecoder.cpp to detect a QR code and get the position.
The code should already detect the contours from an QR code and write it in "this.vecpair;" but it is still not working...
The interface for the decoding in JS code is in the file "threex.jsarucomarker.js" and the function is "QR.Detector();"
And this is my still not finished JS script which is a mix of the ARUCO aruco.js code from JS and the QR logic from the C++ qrdecoder.cpp script.
var QR = QR || {};
QR.Marker = function(id, corners){
this.id = id;
this.corners = corners;
};
QR.Detector = function(){
this.grey = new CV.Image();
this.thres = new CV.Image();
this.homography = new CV.Image();
this.binary = [];
this.cont = [];
this.vec4i = [];
this.contours = this.cont.contours = [];
};
QR.Detector.prototype.detect = function(image){
CV.grayscale(image, this.grey);
CV.adaptiveThreshold(this.grey, this.thres, 2, 7);
this.contours = CV.findContours(this.thres, this.binary);
//this.contours = this.findLimitedConturs(this.thres, 8.00, 0.2 * image.width * image.height);
// console.log(this.contours);
this.vecpair = this.getContourPair(this.contours);
console.log(this.vecpair);
// ARUCO CODE.. MAYBE NOT NECESSARY
//this.candidates = this.findCandidates(this.contours, image.width * 0.10, 0.05, 10);
//this.candidates = this.clockwiseCorners(this.candidates);
//this.candidates = this.notTooNear(this.candidates, 10);
//return this.findMarkers(this.grey, this.candidates, 49);
};
/* C++
struct FinderPattern{
Point topleft;
Point topright;
Point bottomleft;
FinderPattern(Point a, Point b, Point c) : topleft(a), topright(b), bottomleft(c) {}
};
bool compareContourAreas ( std::vector<cv::Point> contour1, std::vector<cv::Point> contour2 ) {
double i = fabs( contourArea(cv::Mat(contour1)) );
double j = fabs( contourArea(cv::Mat(contour2)) );
return ( i > j );
}
*/
QR.Detector.prototype.compareContourAreas = function(c1,c2){
var i = abs(CV.contourArea(c1));
var j = abs(CV.contourArea(c2));
console.log(i+' -- '+j);
return (i > j);
};
/* C++
Point getContourCentre(CONT& vec){
double tempx = 0.0, tempy = 0.0;
for(int i=0; i<vec.size(); i++){
tempx += vec[i].x;
tempy += vec[i].y;
}
return Point(tempx / (double)vec.size(), tempy / (double)vec.size());
}
*/
QR.Detector.prototype.getContourCentre = function(vec){
};
/* C++
bool isContourInsideContour(CONT& in, CONT& out){
for(int i = 0; i<in.size(); i++){
if(pointPolygonTest(out, in[i], false) <= 0) return false;
}
return true;
}
*/
QR.Detector.prototype.isContourInsideContour = function(c_in, c_out){
for(var i = 0; i<c_in.length; i++){
//console.log('-- '+c_out+' -- '+c_in[i]);
if(CV.pointPolygonTest(c_out, c_in[i]) == false) return false;
}
return true;
};
/* C++
vector<CONT > findLimitedConturs(Mat contour, float minPix, float maxPix){
vector<CONT > contours;
vector<Vec4i> hierarchy;
findContours(contour, contours, hierarchy, RETR_TREE, CHAIN_APPROX_SIMPLE);
cout<<"contours.size = "<<contours.size()<<endl;
int m = 0;
while(m < contours.size()){
if(contourArea(contours[m]) <= minPix){
contours.erase(contours.begin() + m);
}else if(contourArea(contours[m]) > maxPix){
contours.erase(contours.begin() + m);
}else ++ m;
}
cout<<"contours.size = "<<contours.size()<<endl;
return contours;
}
*/
QR.Detector.prototype.findLimitedConturs = function(contour, minPix, maxPix){
this.contours = this.cont.contours = [];
this.hierarchy = this.vec4i.hierarchy = [];
CV.findContours(contour, this.contours);
// console.log(this.contours);
var m = 0;
while(m < this.contours.length){
if(CV.contourArea(this.contours[m]) <= minPix){
this.contours.splice(this.contours[0] + m,1);
}else if(CV.contourArea(this.contours[m]) > maxPix){
this.contours.splice(this.contours[0] + m,1);
}else ++ m;
}
// console.log(this.contours.length);
return this.contours;
};
/*
vector<vector<CONT > > getContourPair(vector<CONT > &contours){
vector<vector<CONT > > vecpair;
vector<bool> bflag(contours.size(), false);
for(int i = 0; i<contours.size() - 1; i++){
if(bflag[i]) continue;
vector<CONT > temp;
temp.push_back(contours[i]);
for(int j = i + 1; j<contours.size(); j++){
if(isContourInsideContour(contours[j], contours[i])){
temp.push_back(contours[j]);
bflag[j] = true;
}
}
if(temp.size() > 1){
vecpair.push_back(temp);
}
}
bflag.clear();
for(int i=0; i<vecpair.size(); i++){
sort(vecpair[i].begin(), vecpair[i].end(), compareContourAreas);
}
return vecpair;
}
*/
QR.Detector.prototype.getContourPair = function(contours){
this.vecpair = this.cont.vecpair = [];
var bflag = new Array(contours.length, false); // similar to c++: vector<bool> bflag(contours.size(), false);?
for(var i = 0; i<contours.length - 1; i++){
if(bflag[i] == false){ //similar to c++: if(bflag[i]) continue; ??
var temp = this.cont.temp = [];
//console.log(contours[i]);
temp.push(contours[i]); //similar to c++: temp.push_back(contours[i]); ??
for(var j = i + 1; j<contours.length; j++){
if(this.isContourInsideContour(contours[j], contours[i])){
temp.push(contours[j]);
bflag[j] = true;
// console.log('true');
}
}
if(temp.length > 1){
this.vecpair.push(temp);
}
}
}
//console.log(this.vecpair);
bflag = [];
//console.log(this.vecpair.length);
for(i=0; i<this.vecpair.length; i++){
// sort(this.vecpair[0], this.vecpair[this.vecpair.length], compareContourAreas);
this.vecpair.sort(function(){
console.log('hier');
this.compareContourAreas(this.vecpair[i], this.vecpair[i].length);
});
// console.log(this.vecpair);
}
return this.vecpair;
};
/* C++
void eliminatePairs(vector<vector<CONT > >& vecpair, double minRatio, double maxRatio){
cout<<"maxRatio = "<<maxRatio<<endl;
int m = 0;
bool flag = false;
while(m < vecpair.size()){
flag = false;
if(vecpair[m].size() < 3){
vecpair.erase(vecpair.begin() + m);
continue;
}
for(int i=0; i<vecpair[m].size() - 1; i++){
double area1 = contourArea(vecpair[m][i]);
double area2 = contourArea(vecpair[m][i + 1]);
if(area1 / area2 < minRatio || area1 / area2 > maxRatio){
vecpair.erase(vecpair.begin() + m);
flag = true;
break;
}
}
if(!flag){
++ m;
}
}
if(vecpair.size() > 3){
eliminatePairs(vecpair, minRatio, maxRatio * 0.9);
}
}
*/
QR.Detector.prototype.eliminatePairs = function(){};
/* C++
double getDistance(Point a, Point b){
return sqrt(pow((a.x - b.x), 2) + pow((a.y - b.y), 2));
}
*/
QR.Detector.prototype.getDistance = function(){};
/* C++
FinderPattern getFinderPattern(vector<vector<CONT > > &vecpair){
Point pt1 = getContourCentre(vecpair[0][vecpair[0].size() - 1]);
Point pt2 = getContourCentre(vecpair[1][vecpair[1].size() - 1]);
Point pt3 = getContourCentre(vecpair[2][vecpair[2].size() - 1]);
double d12 = getDistance(pt1, pt2);
double d13 = getDistance(pt1, pt3);
double d23 = getDistance(pt2, pt3);
double x1, y1, x2, y2, x3, y3;
double Max = max(d12, max(d13, d23));
Point p1, p2, p3;
if(Max == d12){
p1 = pt1;
p2 = pt2;
p3 = pt3;
}else if(Max == d13){
p1 = pt1;
p2 = pt3;
p3 = pt2;
}else if(Max == d23){
p1 = pt2;
p2 = pt3;
p3 = pt1;
}
x1 = p1.x;
y1 = p1.y;
x2 = p2.x;
y2 = p2.y;
x3 = p3.x;
y3 = p3.y;
if(x1 == x2){
if(y1 > y2){
if(x3 < x1){
return FinderPattern(p3, p2, p1);
}else{
return FinderPattern(p3, p1, p2);
}
}else{
if(x3 < x1){
return FinderPattern(p3, p1, p2);
}else{
return FinderPattern(p3, p2, p1);
}
}
}else{
double newy = (y2 - y1) / (x2 - x1) * x3 + y1 - (y2 - y1) / (x2 - x1) * x1;
if(x1 > x2){
if(newy < y3){
return FinderPattern(p3, p2, p1);
}else{
return FinderPattern(p3, p1, p2);
}
}else{
if(newy < y3){
return FinderPattern(p3, p1, p2);
}else{
return FinderPattern(p3, p2, p1);
}
}
}
}
*/
QR.Detector.prototype.getFinderPattern = function(){};
This are my added CV functions for the detector
The basic file is "cv.js" from the JavaScript project above https://github.com/jeromeetienne/arplayerforthreejs
This functions should work similar to the C++ versions
pointPolygonTest() = http://docs.opencv.org/2.4/doc/tutorials/imgproc/shapedescriptors/point_polygon_test/point_polygon_test.html
contourArea() = http://docs.opencv.org/2.4/modules/imgproc/doc/structural_analysis_and_shape_descriptors.html#double
//src: http://jsfromhell.com/math/is-point-in-poly
CV.pointPolygonTest = function(poly, pt){
for(var c = false, i = -1, l = poly.length, j = l - 1; ++i < l; j = i)
((poly[i].y <= pt.y && pt.y < poly[j].y) || (poly[j].y <= pt.y && pt.y < poly[i].y))
&& (pt.x < (poly[j].x - poly[i].x) * (pt.y - poly[i].y) / (poly[j].y - poly[i].y) + poly[i].x)
&& (c = !c);
return c;
};
//http://stackoverflow.com/questions/16285134/calculating-polygon-area
CV.contourArea = function(cont){
//console.log('cont: '+cont);
var area = 0; // Accumulates area in the loop
var j = cont.length-1; // The last vertex is the 'previous' one to the first
for (var i=0; i<cont.length; i++)
{
area = area + (cont[j].x+cont[i].x) * (cont[j].y+cont[i].y)
//area = area + (X[j]+X[i]) * (Y[j]-Y[i]);
j = i; //j is previous vertex to i
}
return area/2;
};
Working JavaScript Version wich detects the contours of an QR Code
var CV = CV || {};
CV.Image = function(width, height, data){
this.width = width || 0;
this.height = height || 0;
this.data = data || [];
};
CV.grayscale = function(imageSrc, imageDst){
var src = imageSrc.data, dst = imageDst.data, len = src.length,
i = 0, j = 0;
for (; i < len; i += 4){
dst[j ++] =
(src[i] * 0.299 + src[i + 1] * 0.587 + src[i + 2] * 0.114 + 0.5) & 0xff;
}
imageDst.width = imageSrc.width;
imageDst.height = imageSrc.height;
return imageDst;
};
CV.threshold = function(imageSrc, imageDst, threshold){
var src = imageSrc.data, dst = imageDst.data,
len = src.length, tab = [], i;
for (i = 0; i < 256; ++ i){
tab[i] = i <= threshold? 0: 255;
}
for (i = 0; i < len; ++ i){
dst[i] = tab[ src[i] ];
}
imageDst.width = imageSrc.width;
imageDst.height = imageSrc.height;
return imageDst;
};
CV.adaptiveThreshold = function(imageSrc, imageDst, kernelSize, threshold){
var src = imageSrc.data, dst = imageDst.data, len = src.length, tab = [], i;
CV.stackBoxBlur(imageSrc, imageDst, kernelSize);
for (i = 0; i < 768; ++ i){
tab[i] = (i - 255 <= -threshold)? 255: 0;
}
for (i = 0; i < len; ++ i){
dst[i] = tab[ src[i] - dst[i] + 255 ];
}
imageDst.width = imageSrc.width;
imageDst.height = imageSrc.height;
return imageDst;
};
CV.otsu = function(imageSrc){
var src = imageSrc.data, len = src.length, hist = [],
threshold = 0, sum = 0, sumB = 0, wB = 0, wF = 0, max = 0,
mu, between, i;
for (i = 0; i < 256; ++ i){
hist[i] = 0;
}
for (i = 0; i < len; ++ i){
hist[ src[i] ] ++;
}
for (i = 0; i < 256; ++ i){
sum += hist[i] * i;
}
for (i = 0; i < 256; ++ i){
wB += hist[i];
if (0 !== wB){
wF = len - wB;
if (0 === wF){
break;
}
sumB += hist[i] * i;
mu = (sumB / wB) - ( (sum - sumB) / wF );
between = wB * wF * mu * mu;
if (between > max){
max = between;
threshold = i;
}
}
}
return threshold;
};
CV.stackBoxBlurMult =
[1, 171, 205, 293, 57, 373, 79, 137, 241, 27, 391, 357, 41, 19, 283, 265];
CV.stackBoxBlurShift =
[0, 9, 10, 11, 9, 12, 10, 11, 12, 9, 13, 13, 10, 9, 13, 13];
CV.BlurStack = function(){
this.color = 0;
this.next = null;
};
CV.stackBoxBlur = function(imageSrc, imageDst, kernelSize){
var src = imageSrc.data, dst = imageDst.data,
height = imageSrc.height, width = imageSrc.width,
heightMinus1 = height - 1, widthMinus1 = width - 1,
size = kernelSize + kernelSize + 1, radius = kernelSize + 1,
mult = CV.stackBoxBlurMult[kernelSize],
shift = CV.stackBoxBlurShift[kernelSize],
stack, stackStart, color, sum, pos, start, p, x, y, i;
stack = stackStart = new CV.BlurStack();
for (i = 1; i < size; ++ i){
stack = stack.next = new CV.BlurStack();
}
stack.next = stackStart;
pos = 0;
for (y = 0; y < height; ++ y){
start = pos;
color = src[pos];
sum = radius * color;
stack = stackStart;
for (i = 0; i < radius; ++ i){
stack.color = color;
stack = stack.next;
}
for (i = 1; i < radius; ++ i){
stack.color = src[pos + i];
sum += stack.color;
stack = stack.next;
}
stack = stackStart;
for (x = 0; x < width; ++ x){
dst[pos ++] = (sum * mult) >>> shift;
p = x + radius;
p = start + (p < widthMinus1? p: widthMinus1);
sum -= stack.color - src[p];
stack.color = src[p];
stack = stack.next;
}
}
for (x = 0; x < width; ++ x){
pos = x;
start = pos + width;
color = dst[pos];
sum = radius * color;
stack = stackStart;
for (i = 0; i < radius; ++ i){
stack.color = color;
stack = stack.next;
}
for (i = 1; i < radius; ++ i){
stack.color = dst[start];
sum += stack.color;
stack = stack.next;
start += width;
}
stack = stackStart;
for (y = 0; y < height; ++ y){
dst[pos] = (sum * mult) >>> shift;
p = y + radius;
p = x + ( (p < heightMinus1? p: heightMinus1) * width );
sum -= stack.color - dst[p];
stack.color = dst[p];
stack = stack.next;
pos += width;
}
}
return imageDst;
};
CV.gaussianBlur = function(imageSrc, imageDst, imageMean, kernelSize){
var kernel = CV.gaussianKernel(kernelSize);
imageDst.width = imageSrc.width;
imageDst.height = imageSrc.height;
imageMean.width = imageSrc.width;
imageMean.height = imageSrc.height;
CV.gaussianBlurFilter(imageSrc, imageMean, kernel, true);
CV.gaussianBlurFilter(imageMean, imageDst, kernel, false);
return imageDst;
};
CV.gaussianBlurFilter = function(imageSrc, imageDst, kernel, horizontal){
var src = imageSrc.data, dst = imageDst.data,
height = imageSrc.height, width = imageSrc.width,
pos = 0, limit = kernel.length >> 1,
cur, value, i, j, k;
for (i = 0; i < height; ++ i){
for (j = 0; j < width; ++ j){
value = 0.0;
for (k = -limit; k <= limit; ++ k){
if (horizontal){
cur = pos + k;
if (j + k < 0){
cur = pos;
}
else if (j + k >= width){
cur = pos;
}
}else{
cur = pos + (k * width);
if (i + k < 0){
cur = pos;
}
else if (i + k >= height){
cur = pos;
}
}
value += kernel[limit + k] * src[cur];
}
dst[pos ++] = horizontal? value: (value + 0.5) & 0xff;
}
}
return imageDst;
};
CV.gaussianKernel = function(kernelSize){
var tab =
[ [1],
[0.25, 0.5, 0.25],
[0.0625, 0.25, 0.375, 0.25, 0.0625],
[0.03125, 0.109375, 0.21875, 0.28125, 0.21875, 0.109375, 0.03125] ],
kernel = [], center, sigma, scale2X, sum, x, i;
if ( (kernelSize <= 7) && (kernelSize % 2 === 1) ){
kernel = tab[kernelSize >> 1];
}else{
center = (kernelSize - 1.0) * 0.5;
sigma = 0.8 + (0.3 * (center - 1.0) );
scale2X = -0.5 / (sigma * sigma);
sum = 0.0;
for (i = 0; i < kernelSize; ++ i){
x = i - center;
sum += kernel[i] = Math.exp(scale2X * x * x);
}
sum = 1 / sum;
for (i = 0; i < kernelSize; ++ i){
kernel[i] *= sum;
}
}
return kernel;
};
CV.findContours = function(imageSrc, binary){
var width = imageSrc.width, height = imageSrc.height, contours = [],
src, deltas, pos, pix, nbd, outer, hole, i, j;
src = CV.binaryBorder(imageSrc, binary);
deltas = CV.neighborhoodDeltas(width + 2);
pos = width + 3;
nbd = 1;
for (i = 0; i < height; ++ i, pos += 2){
for (j = 0; j < width; ++ j, ++ pos){
pix = src[pos];
if (0 !== pix){
outer = hole = false;
if (1 === pix && 0 === src[pos - 1]){
outer = true;
}
else if (pix >= 1 && 0 === src[pos + 1]){
hole = true;
}
if (outer || hole){
++ nbd;
contours.push( CV.borderFollowing(src, pos, nbd, {x: j, y: i}, hole, deltas) );
}
}
}
}
return contours;
};
CV.borderFollowing = function(src, pos, nbd, point, hole, deltas){
var contour = [], pos1, pos3, pos4, s, s_end, s_prev;
contour.hole = hole;
s = s_end = hole? 0: 4;
do{
s = (s - 1) & 7;
pos1 = pos + deltas[s];
if (src[pos1] !== 0){
break;
}
}while(s !== s_end);
if (s === s_end){
src[pos] = -nbd;
contour.push( {x: point.x, y: point.y} );
}else{
pos3 = pos;
s_prev = s ^ 4;
while(true){
s_end = s;
do{
pos4 = pos3 + deltas[++ s];
}while(src[pos4] === 0);
s &= 7;
if ( ( (s - 1) >>> 0) < (s_end >>> 0) ){
src[pos3] = -nbd;
}
else if (src[pos3] === 1){
src[pos3] = nbd;
}
contour.push( {x: point.x, y: point.y} );
s_prev = s;
point.x += CV.neighborhood[s][0];
point.y += CV.neighborhood[s][1];
if ( (pos4 === pos) && (pos3 === pos1) ){
break;
}
pos3 = pos4;
s = (s + 4) & 7;
}
}
return contour;
};
CV.neighborhood =
[ [1, 0], [1, -1], [0, -1], [-1, -1], [-1, 0], [-1, 1], [0, 1], [1, 1] ];
CV.neighborhoodDeltas = function(width){
var deltas = [], len = CV.neighborhood.length, i = 0;
for (; i < len; ++ i){
deltas[i] = CV.neighborhood[i][0] + (CV.neighborhood[i][1] * width);
}
return deltas.concat(deltas);
};
CV.approxPolyDP = function(contour, epsilon){
var slice = {start_index: 0, end_index: 0},
right_slice = {start_index: 0, end_index: 0},
poly = [], stack = [], len = contour.length,
pt, start_pt, end_pt, dist, max_dist, le_eps,
dx, dy, i, j, k;
epsilon *= epsilon;
k = 0;
for (i = 0; i < 3; ++ i){
max_dist = 0;
k = (k + right_slice.start_index) % len;
start_pt = contour[k];
if (++ k === len) {k = 0;}
for (j = 1; j < len; ++ j){
pt = contour[k];
if (++ k === len) {k = 0;}
dx = pt.x - start_pt.x;
dy = pt.y - start_pt.y;
dist = dx * dx + dy * dy;
if (dist > max_dist){
max_dist = dist;
right_slice.start_index = j;
}
}
}
if (max_dist <= epsilon){
poly.push( {x: start_pt.x, y: start_pt.y} );
}else{
slice.start_index = k;
slice.end_index = (right_slice.start_index += slice.start_index);
right_slice.start_index -= right_slice.start_index >= len? len: 0;
right_slice.end_index = slice.start_index;
if (right_slice.end_index < right_slice.start_index){
right_slice.end_index += len;
}
stack.push( {start_index: right_slice.start_index, end_index: right_slice.end_index} );
stack.push( {start_index: slice.start_index, end_index: slice.end_index} );
}
while(stack.length !== 0){
slice = stack.pop();
end_pt = contour[slice.end_index % len];
start_pt = contour[k = slice.start_index % len];
if (++ k === len) {k = 0;}
if (slice.end_index <= slice.start_index + 1){
le_eps = true;
}else{
max_dist = 0;
dx = end_pt.x - start_pt.x;
dy = end_pt.y - start_pt.y;
for (i = slice.start_index + 1; i < slice.end_index; ++ i){
pt = contour[k];
if (++ k === len) {k = 0;}
dist = Math.abs( (pt.y - start_pt.y) * dx - (pt.x - start_pt.x) * dy);
if (dist > max_dist){
max_dist = dist;
right_slice.start_index = i;
}
}
le_eps = max_dist * max_dist <= epsilon * (dx * dx + dy * dy);
}
if (le_eps){
poly.push( {x: start_pt.x, y: start_pt.y} );
}else{
right_slice.end_index = slice.end_index;
slice.end_index = right_slice.start_index;
stack.push( {start_index: right_slice.start_index, end_index: right_slice.end_index} );
stack.push( {start_index: slice.start_index, end_index: slice.end_index} );
}
}
return poly;
};
CV.warp = function(imageSrc, imageDst, contour, warpSize){
var src = imageSrc.data, dst = imageDst.data,
width = imageSrc.width, height = imageSrc.height,
pos = 0,
sx1, sx2, dx1, dx2, sy1, sy2, dy1, dy2, p1, p2, p3, p4,
m, r, s, t, u, v, w, x, y, i, j;
m = CV.getPerspectiveTransform(contour, warpSize - 1);
r = m[8];
s = m[2];
t = m[5];
for (i = 0; i < warpSize; ++ i){
r += m[7];
s += m[1];
t += m[4];
u = r;
v = s;
w = t;
for (j = 0; j < warpSize; ++ j){
u += m[6];
v += m[0];
w += m[3];
x = v / u;
y = w / u;
sx1 = x >>> 0;
sx2 = (sx1 === width - 1)? sx1: sx1 + 1;
dx1 = x - sx1;
dx2 = 1.0 - dx1;
sy1 = y >>> 0;
sy2 = (sy1 === height - 1)? sy1: sy1 + 1;
dy1 = y - sy1;
dy2 = 1.0 - dy1;
p1 = p2 = sy1 * width;
p3 = p4 = sy2 * width;
dst[pos ++] =
(dy2 * (dx2 * src[p1 + sx1] + dx1 * src[p2 + sx2]) +
dy1 * (dx2 * src[p3 + sx1] + dx1 * src[p4 + sx2]) ) & 0xff;
}
}
imageDst.width = warpSize;
imageDst.height = warpSize;
return imageDst;
};
CV.getPerspectiveTransform = function(src, size){
var rq = CV.square2quad(src);
rq[0] /= size;
rq[1] /= size;
rq[3] /= size;
rq[4] /= size;
rq[6] /= size;
rq[7] /= size;
return rq;
};
CV.square2quad = function(src){
var sq = [], px, py, dx1, dx2, dy1, dy2, den;
px = src[0].x - src[1].x + src[2].x - src[3].x;
py = src[0].y - src[1].y + src[2].y - src[3].y;
if (0 === px && 0 === py){
sq[0] = src[1].x - src[0].x;
sq[1] = src[2].x - src[1].x;
sq[2] = src[0].x;
sq[3] = src[1].y - src[0].y;
sq[4] = src[2].y - src[1].y;
sq[5] = src[0].y;
sq[6] = 0;
sq[7] = 0;
sq[8] = 1;
}else{
dx1 = src[1].x - src[2].x;
dx2 = src[3].x - src[2].x;
dy1 = src[1].y - src[2].y;
dy2 = src[3].y - src[2].y;
den = dx1 * dy2 - dx2 * dy1;
sq[6] = (px * dy2 - dx2 * py) / den;
sq[7] = (dx1 * py - px * dy1) / den;
sq[8] = 1;
sq[0] = src[1].x - src[0].x + sq[6] * src[1].x;
sq[1] = src[3].x - src[0].x + sq[7] * src[3].x;
sq[2] = src[0].x;
sq[3] = src[1].y - src[0].y + sq[6] * src[1].y;
sq[4] = src[3].y - src[0].y + sq[7] * src[3].y;
sq[5] = src[0].y;
}
return sq;
};
CV.isContourConvex = function(contour){
var orientation = 0, convex = true,
len = contour.length, i = 0, j = 0,
cur_pt, prev_pt, dxdy0, dydx0, dx0, dy0, dx, dy;
prev_pt = contour[len - 1];
cur_pt = contour[0];
dx0 = cur_pt.x - prev_pt.x;
dy0 = cur_pt.y - prev_pt.y;
for (; i < len; ++ i){
if (++ j === len) {j = 0;}
prev_pt = cur_pt;
cur_pt = contour[j];
dx = cur_pt.x - prev_pt.x;
dy = cur_pt.y - prev_pt.y;
dxdy0 = dx * dy0;
dydx0 = dy * dx0;
orientation |= dydx0 > dxdy0? 1: (dydx0 < dxdy0? 2: 3);
if (3 === orientation){
convex = false;
break;
}
dx0 = dx;
dy0 = dy;
}
return convex;
};
CV.perimeter = function(poly){
var len = poly.length, i = 0, j = len - 1,
p = 0.0, dx, dy;
for (; i < len; j = i ++){
dx = poly[i].x - poly[j].x;
dy = poly[i].y - poly[j].y;
p += Math.sqrt(dx * dx + dy * dy) ;
}
return p;
};
CV.minEdgeLength = function(poly){
var len = poly.length, i = 0, j = len - 1,
min = Infinity, d, dx, dy;
for (; i < len; j = i ++){
dx = poly[i].x - poly[j].x;
dy = poly[i].y - poly[j].y;
d = dx * dx + dy * dy;
if (d < min){
min = d;
}
}
return Math.sqrt(min);
};
CV.countNonZero = function(imageSrc, square){
var src = imageSrc.data, height = square.height, width = square.width,
pos = square.x + (square.y * imageSrc.width),
span = imageSrc.width - width,
nz = 0, i, j;
for (i = 0; i < height; ++ i){
for (j = 0; j < width; ++ j){
if ( 0 !== src[pos ++] ){
++ nz;
}
}
pos += span;
}
return nz;
};
CV.binaryBorder = function(imageSrc, dst){
var src = imageSrc.data, height = imageSrc.height, width = imageSrc.width,
posSrc = 0, posDst = 0, i, j;
for (j = -2; j < width; ++ j){
dst[posDst ++] = 0;
}
for (i = 0; i < height; ++ i){
dst[posDst ++] = 0;
for (j = 0; j < width; ++ j){
dst[posDst ++] = (0 === src[posSrc ++]? 0: 1);
}
dst[posDst ++] = 0;
}
for (j = -2; j < width; ++ j){
dst[posDst ++] = 0;
}
return dst;
};
//src: http://jsfromhell.com/math/is-point-in-poly
CV.pointPolygonTest = function(poly, pt){
for(var c = false, i = -1, l = poly.length, j = l - 1; ++i < l; j = i)
((poly[i].y <= pt.y && pt.y < poly[j].y) || (poly[j].y <= pt.y && pt.y < poly[i].y))
&& (pt.x < (poly[j].x - poly[i].x) * (pt.y - poly[i].y) / (poly[j].y - poly[i].y) + poly[i].x)
&& (c = !c);
return c;
};
//http://stackoverflow.com/questions/16285134/calculating-polygon-area
CV.contourArea = function(cont){
//console.log('cont: '+cont);
var area = 0; // Accumulates area in the loop
var j = cont.length-1; // The last vertex is the 'previous' one to the first
for (var i=0; i<cont.length; i++)
{
area = area + (cont[j].x+cont[i].x) * (cont[j].y+cont[i].y);
//area = area + (X[j]+X[i]) * (Y[j]-Y[i]);
j = i; //j is previous vertex to i
}
return area/2;
};

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